1. Field of the Art
This invention relates to a catalyst component for polymerization of olefins. More particularly, the present invention relates to a solid catalyst component containing a transition metal of the Ziegler type catalyst.
When polymerization of an olefin is performed by the use of the solid catalyst component of the present invention as the transition metal component of a Ziegler catalyst, a polymer having high activity, excellent stereoregularity and good polymer properties in bulk density, particle shape, particle size, particle distribution and the like can be produced.
It has been known in the art that a highly active catalyst can be obtained by the use of a magnesium compound such as a magnesium halide, a magnesium oxyhalide, a dialkylmagnesium, an alkylmagnesium halide, a magnesium alkoxide, or a complex of a dialkylmagnesium with an organoaluminum, etc., as the carrier for a transition metal compound such as titanium compound, and a number of relative inventions have been proposed.
In these prior art techniques, the catalyst activity is high to some extent, but the polymer properties of the polymer produced are not entirely satisfactory and improvements thereof have been desired. The polymer properties are extremely important in polymerization processes such as slurry polymerization and gas phase polymerization. If the polymer properties are poor, polymer adhesion within the polymerization vessel or difficulty in polymer withdrawal from the polymerization vessel, etc., may be caused.
Also, the polymer concentration within a polymerization vessel is intimately related with the polymer properties and cannot be made high unless the polymer properties are good. It is very disadvantageous in industrial production when the polymer concentration within a polymerization vessel cannot be made high.
Also, in preparation of a large number of catalyst components of the prior art, the transition metal component is used in a large amount. This is very inconvenient for the preparation of the catalyst. It is necessary to remove much of the transition metal component not contained as the catalyst component from the catalyst component, and for that purpose much solvent, etc., are required, which leads to increase in production cost of the catalyst.
Also, it is necessary to subject the transition metal components which have become unnecessary to decomposition treatment, whereby generation of halogen gas, a hydrogen halide, etc., occurs in most cases and is deleterious for environmental hygiene. Accordingly, improvement in the quantity of transition metal component has been desired.
2. Prior Art
Ziegler-type catalysts have been well known in the art as catalysts for stereoregular polymerization of olefins, and various methods have been proposed for further improvement of their activity and stereoregularity, as is also well known in the art.
Examples of these various improvement methods are those as proposed in Japanese Patent Publication No. 359/1985. In these known techniques, polymers of high activity and good stereoregularity are described as being obtainable, but further improvement and enhancement of stereoregularity, polymer properties of the polymer formed (bulk density, etc.) and the catalyst active level (the so-called "post-treatment" during production polymer cannot be completely omitted), etc., have been still desired under the present circumstances.